With rapid advances in wireless networking, Internet protocol (IP) mobility has become more common for mobile users in maintaining connectivity, and allowing communication with other mobile users. Information on the location of mobile units may be desirable for various purposes. For example, in emergency services such as fire departments, it may be desirable to have real-time information on the location of each firefighter. Another example involves law enforcement, where dynamic positions of police officers can be helpful in managing various situations and/or operations. In these cases, identifying a particular location in need of help, directing a search path, as well as avoiding unnecessary actions, can be useful.
Mobile devices such as mobile phones, mobile smart phones, laptops computers, etc., are known that transmit media information in real time using packetized formats. There is a desire for such mobile devices to also indicate their location by transmitting location information. Some conventional approaches for providing location information use, during a setup time, signaling messages that include the location information, with subsequent updating from time to time. However, such approaches may require excessive signaling if the location changes rapidly. Also, such signaling paths might be different than the media paths. Furthermore, secrecy often is desired. Intermediate nodes along the signaling paths may inadvertently disclose information, so that location information embedded in signaling paths might be disclosed via intermediate nodes. For real time data, such a media data, one alternate approach is to embed the location information into the packets of Real-time Transport Control Protocol (RTCP), which is often used to pair with one media stream for providing more information about the stream. However, many mobile devices do not support RTCP. Some intermediate devices, such as firewalls, may block RTCP for reasons of security. Furthermore, RTCP, when used, often has RTCP packets being sent relatively infrequently. Yet another known approach is to define an extension to the header Real Time Protocol (RTP) packets in order to carry location information, and to thus embed location information in RTP headers using the defined extension. Compressed RTP (cRTP) is known and often used to pass RTP packets over some slow links. Such cRTP cannot work well with such a RTP header extension, especially when real-time location information is heavy.